Cable locks are known in the art for securing moveable objects to stationary objects. Typically a cable is threaded through the object and secured around an immovable object, thus anchoring the item to the immovable object. Cable locks are also used to secure parts of moveable objects to each other so that they cannot be easily transported or opened. For example, bicycles and motorcycles are secured by threading a cable around the bike frame and at least one wheel and locking the cable ends together such that the cable prevents the bike wheels from rolling. In this manner the bike cannot be rolled away. The bike can be lifted and moved, however, if it is not secured to an immobile object.
Service trucks often carry expensive equipment that is too large to be locked in a tool box, but small enough to be carried away by a thief, loose in the bed of truck. Pick-up owners also carry equipment and toys loose in the bed of the trucks. U.S. Pat. No. 5,349,834 issued to Davidge illustrates a cable lock adhesively secured to the bed of a pick-up truck to secure equipment such as a chainsaw. U.S. Pat. 5,531,082 issued to Wolk discloses a portable security case which contains the objects to be secured. A cable integral with the case is locked around an immovable object such as a post.
Thieves can defeat cable locks by severing the cable, breaking the lock mechanism, or carting the moveable object away, as in the case of a bicycle. Alarmed cable locks have been developed to alert the owner if the lock has been defeated. For example, U.S. Pat. No. 4,057,986 issued to Zolke describes a portable, battery-powered cable lock that sounds an alarm if the cable is cut. The disadvantage of this type of alarmed lock is that the alarm sounds only after the lock has been defeated. Since the cable must have been severed for the alarm to sound, by the time the owner responds to the alarm the thief may have escaped with the previously secured item. It is desirable to have a loud alarm that sounds when a thief attempts to break the cable or lock, or when the object is lifted to be carried away.
Tamper resistant padlocks are described in the prior art. U.S. Pat. No. 5,404,735 issued to Hsieh discloses a battery-powered alarmed padlock. The device is a padlock with a large U-shaped shackle having a vibration switch that triggers the alarm if abnormal vibration is detected. This lock is unsuitable to be used in vehicles which vibrate when in motion, and is limited in the size and shape of articles it can secure because of the rigid shackle. A cable lock is desired that can secure large items and detect tampering, but is relatively insensitive to vibration so that it can be used in a vehicle.
Therefore, it is an object of this invention to provide an alarmed cable lock that sounds an alarm before the lock is defeated so that potential thieves are warned away. It is an object of this invention to provide an alarmed cable lock which can detect tampering, but is relatively insensitive to vibration so that it can be used in a vehicle without giving false alarms. It is a further object of this invention to provide an alarmed cable lock to secure loose equipment to, or within, a vehicle.